Ab initio study of MoS2 and Li adsorbed on the (10
0) face of MoS2
Abstract
Periodic
Hartree–Fock methods were used to calculate the geometric and electronic properties of 2H-MoS2
, 1T-MoS2, the (100) surface of MoS2 and Li adsorbed thereon. For the calculations, the structures were
generated by an extension of unit cells to the respective bulk structures (1T- and 2H-MoS2) or by cutting sections,
each consisting of six or eight layers of sulfur and molybdenum, from a crystal ((10
0) surface
of MoS2 with and without adsorbed Li). Structural optimization was performed with a post Hartree–Fock
DFT correlation correction. The calculated structures of 2H-MoS2 and 1T-MoS2
are in good agreement with
0) surface of 2H-MoS2 leads to a minor reconstruction of the surface accompanied by the formation
of S2 species and an inward relaxation of Mo atoms. Adsorption of Li on this surface is favoured
in the high symmetry positions above the van der Waals gap. Relaxation of the Li-covered (10
0) surface
of 2H-MoS2 shifts the Li atoms towards the S2 pairs and closer to the surface. Upon adsorption, the system becomes
metallic and delocalized surface states
form at
the Fermi level
due to electron transfer
processes from the Li atoms to the surface layers of MoS2.